Air classifier



. 1927' A. H. s'rsaams AIn'cLAssIFIER Filed Jan.5. 1926 2 Sheets-$heat l INVE/V TOR 1444 JKXWLO 1927' A. H. STEBBINS AIR CLASSIFIER Filed Jan. 5, 1926 2 Sheets-Sheet 2 //V I/EN 70 l? ATTORNE Patented May 24, 1927.

UNITED STATES ALBERT H. STEBBINS, 01? LOS ANGELES,. CALIFORNIA AIR GLASSIFIER.

Application filed January This invention relates to air classifiers of the type in which the materials to be treated are caused to whirl in an annular chamber, that both monumtum and centrifugal force may be employed in effecting the separation.

The clussifier'o'l the present. invention is designed more particularly for use in treating fine, dust-like materials, but it is difiicult to remove the very iine particles. without also removing the slightly larger partielse, and it is therefore desirable that the materials being treated be repeatedly subjected to the separating-action.

One important feature of the present invention therefore resides in an air classifier having an annular passage in which air bcaring the materials to be treated is caused to whirl, and in means for extracting air from the annular passage at a plurality of points about its axis to remove from the passage the liner particles whirling therein.

Another feature of the invention resides in the construction whereby air from the exterior of the classifier is drawn inwardly across the-annular passage to carry off the lighter particles whirling in the passage.

Another feature of the invention resides in the construction whereby the'streugth of the air which is withdrawn from the annu lar passage at different points about its axis 7 may be varied as desired to vary the operation at each point of withdrawal.

Other features of the invention and novel combination of parts in addition to the above will be hereinafter described in connection with the accompanying drawings which illustrate one good practical form of the invention.

In the drawin 's,

Fig. 1 is a si e elevation with parts in section of a classifier constructed in accordance with the present invention;

Fig. 2 on an enlarged'scale is a side elevation of the separating casing of Fig. 1;

Fig. 3 'is a sectional view taken on me line of Fig. 2;

Fig. 4 is a. perspective view of the line rior-structure of the casing of Fig. 2; and F Fig). 5 is a top plan View of the casing of The classifier of the present invention 18 designed moreparticularly for the treat:

ment of fine, dust-like. materials and the receptacle in which the. separating action takes 5, 192s.v Serial u 79,459.

place preferably. consists oi i'an outer casing 10 and an inner casing 11 arranged to form the annular air passage'12 between th'emiin which air bearing the materials to be treat ed may whirl. The material laden. air in the construction shown is delivered into the upper portion of the annulanpassuge 12 by the pipe 13 which preferably slopes downunrdly as shown, and extends spirally around the upper portion of the inner casing 11, as indicated by 13" to impart a down- \vardly whirling movement to the air and materials delivered into the passage 12.

The inclined pipe 13 is connected with the air supply conduit 14, and air under aressure may be delivered to this conduit y a fan or blower 15, and since the air ispret' erably -forced into the annular passage 12 in the form of a strong air blast, the fan or blower 15. should be constructed so. that it will supply air to the conduit 14 under relatively high pressure.

The iine, dust-like materials to be sepa rated are carried into the air passage 12 by theblast of air, and means :is therefore shownin the present case for delivering the materials to be treated into the conduit 14. This means consists of a hop er 16 having a relatively long, downwar lyextending neck 17, the. lower end of which is connected to an enlargement 18 formed upon the conduit 14.' It is desirable to provide means for regulating the flow of the materials from the hopper 16 into the conduit 14, and while various m ans might be provided to this end, in the present case a rotating disk or spreader 19 is'provided which is supported adjacent the lower end of the neck 17 so that it rotates in a horizontal plane. This disk is secured to the operating shaft 20 05 journaled in the brackets 21 and 22 and theshaft may be rotated by the driving pulley 23. The opening between the upper face of the disk and the lower end of the neck 17 may be varied as desired'by adjusting the nuts 24: which serve to raise and lower the shaft 20. The arrangement is such that as the disk rotates theniaterials that aredelivered upon. the upperface of the disk by 'the feed hopper will be thrown outwardly into the ail-passing thru the. conduit 14. Due to the relatively high pressureof the air within the conduit 14 it will tendto force its Way up thruthe materials within the hopper .16; this hopper is therefore made relatively tall or is rovided with a long neck 17 so that air wi 1 not be'able to pass up thru the entire mass of materials.

As stated, in treating fine, dust-like materials it is difficult to completely separate the very line particles from the slightly heavier particles, and in accordance with the present invention means is provided for ex- .tracting air from the annular passage 12 at a plurality oftpoints about the axis of the classifier. To this end the inner casing 11 is divided longitudinally into a plurality of separate 'coi'npairtments (three being shown in the present case) which are desi 'nated by 25,26and27, andare formed by the partitions 28 within the casing ll. 'lheconipartments 25,26 and 27 are provided with the inlet openings or'slots29, 30 and 31, which preferably extend lengthwise of the casing 11 a substantial distance, as will be apparent from Figs. 2 and 4. As the air hearing the materialstd be treated is delivered into the annular passage 12 by the pipe 13 it successively passes the slots 29, and 31, thru each of which slots currents of air are drawn into thei-cspective co npa-rtments by suction means to be described, and these currents of air serve to draw into these compartments the lighter particles within the annular passage 12. The heavier particles whirling within this passage will be thrown outwardly bycentri'fugal force against the wall of the outer casing 10 and this will prevent them .t'rom being drawn into'the compartments 25,26 and 27 with the lighter particles, The momentum of these heavierv particles will also help. to keep them from being drawn inwardly thru the slots just mentioned. The heavierparticles as-they continue to whirl in. the annular passage 12 .will move downwardly therein until collector 37 0 any desired construction for further treatment. In the construction shown air is exhausted from the compartments 26 and 27 by the ran 38, and the pipe 39 connected to the upperend of the third compartment 27 leads 5 directly to the fan 38 while the pipe 40 leading from the suction compartment 26 carries its materials to thesuc-tion dust extractor 41 to remove the heavier particles within the air before the air passeswonto the fan 38 thru the pipe 42. The heavier materials separated out of the air by the dust extractor a1 may be delivered by this dust extractor to the feed hopper 1&5 for retreatment, and the strength ofthe air within the various pipes just mentioned may be controlled as desired by adjusting the valves 43. The air delivered by the fan 38 and which contains very line dust may be delivered to a dust extractor 4 1 for further treatment.

It may be desirable to admit air from the atmosphere into the annular passage 12 at points opproxiniately opposite the slots 29, :30 and 31, and to this end, in the present case, the casing 10 is provided with the inlet slots or openin 's i6 and i7 formed to admit air into t is passage 12 near its upper end, where the force or the air blast is greatest. Each of the slotsvjust mentioned as 'loimed iathe outer casing 10, is preterably provided with a housing such as designated by is which may be riveted or otherwise secured to the outer face of the casing over the air inlet slot. Each of these housings-i8 is provided with an openingthe size oi which may be varied by adjusting the sliding; gate As a result of this construction a regulated amount oi air may enter each of the slots i5, at) and 'i? near the upper end of the annular passage 12, to pass across the path of the air whirling within this passage to carry the lighter particles thru the respective slots 29, 30 and 31.

From the 'foregoing description, when read in connect-ion with the d'rawii'igs, it will be seen that the dust laden air whirling within the annular passage 12 is successively subjected to the separating action of the air drawn inwaidly thru the slots 29, b0 and 31 so that soni'e oi the fine particles within the whirling air will 'passinwardly thru each of these slots, and since these slots extend downwardly thruout. substantially the entire length of the casing 10, they will serve to extract some of the iiner particles "from the air each time the air passes these slots in moving spirally downwardly within the annular passage. The separating; operation effected by the chan'ibers 25; 26 and 27 may be varied as desired by adjusting the air inlet gates a!) and by adjusting'the air valves 56 and a3 to control the suction action in each of tliesc'receptacles A small amount of. the lighter materials may settle within the lower portion of the compartments 25, 26 and 27 and these compartments may be cleaned out l lOlll time to time by drawing these materials out thru the hoppers 50 at the'lower end of the compartments.

What is claimed is: v

1. An air classifier, comprising in combination, an inner casing divided longitudinally into different compartments and having' slots formed in the side walls of the casing and-leading into each compartment, an outer casing surrounding the inner casing and forming an annular air passage between the outer and inner casing, means for deliveringair bearing the materials to be treated into the annular passage with a whirling movement, separate means for exhausting air from each of said compartments to draw inwardly through said slots the lighter particles withinthe annular passage, and means for indepeinlentlyregulating the strength of the air exhaustfor each compartment to thereby vary the size of the particles that will be drawn into a particular compartment.

2. An air classifier, con'iprising in co1nbination,.an outer casing and an inner casing having an annular air passage betweenthem and the innercasing havin-ga plurality of' ion itudinally extending slots formed lhroug relation to'euch otheiymeans 'ior introducing air intothe annular passage through the wall of the outer casing at points opposite said slots, means for delivering air bearing the materials to be treated into said annular passage with a whirling movement, and suction means for drawing air from the openings in the outer wall 01 the casing across the passage into said slots at right angles to the path of the air traveling in said passage to thereby draw into the inner casing the lighter particles whirling in the annular passa 'e.

3. 11 air classifier, comprising in combination, an inner casing divided longitudinally into different noncommunicating compartments and having slots formed in the side walls of the casing and leading into each compartment, an outer casing surrounding the inner casing and forming an annular air passage between the outer, and

innercasing, means for delivering air hearing the materials to be treated into the annular passage with a whirling movement that the air will successively pass the angularly disposed slots as it travelsuround said passage, means for esliaustin air from each of said compartments to (raw inwardly through said slots the lighter particles and the construction being such that a dili'erent gradeof the lighter particles will he collected'in each compartment as a result of the positioning of the inlet slots around the passage dilfercnt distances from said air delivering means.

el. An air classifier, comprising in combination, an inner circular casing having slots providedin its side walls in angular spaced relation to each other, an outer casing surrounding the inner casing to form an annular passage therebetween and having air inlet openings in its outer walls opposite said slots and arranged its side walls in angular-1y spaced so tha-t the air thus introduced may-travel directly across the annular passage into the adjacent slot, means for. delivering-unhearingthe materialsto he treated into the annular passage \vitlra whirling movement, means tot-drawing air inward through said slots from said inlets to produce air currents -passing transversely through the whirling air currents within the passage to draw the lighter particles into saidslot, and inde pendenlly adjustable means for controlling the amount 01' air admitted to the annular passage through each ofsaid openings in the outer casing. 1 I v 5. An air classifier, comprising in combination, an inner casing divided into different compartments and having slots formed through the side walls of the casing and leading 'into each compartment, an outer casing surrounding the inner casing and forming an. annular passage between them, means for delivering a blast of air bearil'ig the materials .to he treated into the passage to whirl therein, means for exhaustmg an from said compartmentsto draw inwardly thru said slots thelighter-[particles in the annular passage, and separate means for varying the strength of the air in each I compartment. 1 r ,6. An air classifier, comprising in combination, an inner circular casing having a longitudinal slot provided in its annular wall, an outer casing.sun-omitting the inner casing and forming an annular passage therebetween, meansfor delivering air hearing the materials to he treated into the annular passage with a whirling movement, means for introducing air into the passage thru the outer wall of the casing at a point opposite said slot and arranged so that the air thus introduced may travel directly across the annular passage into said slot, and means for drawing air inward thru said slot from the opening in the outer wall to pro 'duce air currents passing transversely thru the whirling air currents within the passage to draw thelighter-particles into said slot.

7. An air classifier, comprising in combination, an inner circular casing having slots provided in its annular wall in spaced relation about its axis, an outer casing surrounding the inner casing to form an annular passage therebetween and having air inlet openings in its outer wall opposite said slots and arranged so that the air thus introduced may travel directly across the an nular path into the adjacent slot, means for delivering air bearing the materials to be treated into the annular passage with a whirlingmovement, and means for drawing air inward thru said slots from said inlets toproduce air currents passing transversely thru the whirling air. currents within the passa e to draw the lighter particles into said 5 ots.

8. In combination with an air classifier having ave-using in which the separation of the materials is effected, a conduit for forcing air under pressure into the casing, a feed hopper for delivering materials to the conduitso that they are carried into the casing by the air, and a rotating disk adapted to'regulate the-flow of the n'iaterialsircm the hopper into the conduit and positioned above the path of the air traveling within said conduit and justsuliicient distance from a fixed portion of the feed hopper to provide a material discharge opening the size of which regulates the rate of teed.

9. In combination with a air classifier having a casing in which the separation of the materials is elfecteth'a conduit for 'l'orcing air under pressure into the casing, a i'ced hopper. for delivering materials to the conduit so that they are carried into the casing by the air, a rotating disk disposed at the lower end of the hopper to rotate in a horizontnl plane for controlling the feed of the materials to the conduit, said disk being positioned above the path 01 the air traveling within said conduit and just snflicient distance from the lowiend of the hopper to provide material discharge opening the size of which regulates the rate 0t feed, and means for rotating the disk to feed the n1a terials to the conduit.

10. in combination with an air classifier having a casing in which the separation of the materials is effected, a conduit for foroing air under pressure into the casing, a feed hopper for delivering materials to the conduit so that they are carried into the casing by the air, a rotating disk disposed at the lower end of the hopper ,to rotate in a horizontal plane for controlling the feed of the n'mterials to the conduit, means for supporting the disk different distances from the end of the hopper and for adj listing it relatively to the hopper to vary the size of the opening between the disk and hopper and thereby regulate the feed, and means "for rotating the disk to feed the materials to the. conduit.

11. An air classifier, comprising in co1nbination, an inner circular *asing divided into dill'erent compartments and having a slot leading into each: con'ipartn'ient, an outer casing surrounding the inner casing and forming an air pus-sage tl'ierebetween,'Ineans for delivering a blast of air-bearing the materials to he treated intothe passage to whirl, therein, means for exhausting air from each of said compartments to draw inwardly thrn said -slots the lighter particle; in the annular passage, dust extractors -;-o nnerted to said compartments for removing the dust from the air that enters said coinpartn'icntre, and means for exhausting the dust laden air from said compartments and passing it through the dust extractors.

in testimony whereof, I have signed my mine to this specification.

ALBERT I-I. STEBBINS. 

